Effect of immersion on intrapulmonary pressure

1965 ◽  
Vol 20 (6) ◽  
pp. 1261-1266 ◽  
Author(s):  
A. S. Jarrett
Keyword(s):  
Center Of Pressure ◽  
Water Immersion ◽  
Breath Holding ◽  
Regression Equations ◽  
Volume Relaxation ◽  
Diving Physiology ◽  
Volume Curve ◽  
Pressure Axis ◽  
Pressure Volume Curve ◽  
Relaxation Curves

Pressure-volume relaxation curves have been determined for relaxed, breath-holding subjects lying and sitting in air and water. Immersion in water resulted in a marked increase in intrapulmonary pressure, the whole pressure-volume curve appearing to be shifted along the pressure axis. From the regression equations of the four curves the pressures at normal relaxed chest volume were calculated, and the center of pressure of the immersed chest shown to lie 19 cm below and 7 cm behind the sternal angle. The significance of this to the positioning of a diver's demand valve is discussed. center of pressure of thorax; immersion and chest volume; eupneic pressure; diving physiology; underwater respiration Submitted on September 10, 1964

scholarly journals Broad individual immersion-scattering of respiratory compliance likely substantiates dissimilar breathing mechanics

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Olivier Castagna ◽  
Guillaume Michoud ◽  
Thibaut Prevautel ◽  
Antoine Delafargue ◽  
Bruno Schmid ◽  
...  
Keyword(s):  
Respiratory System ◽  
Water Immersion ◽  
Work Of Breathing ◽  
Adult Group ◽  
Respiratory Compliance ◽  
Volume Curve ◽  
Pressure Volume Curve ◽  
Diving Medicine ◽  
Breathing Mechanics ◽  
Diverse Individual

AbstractHead-out water immersion alters respiratory compliance which underpins defining pressure at a “Lung centroid” and the breathing “Static Lung Load”. In diving medicine as in designing dive-breathing devices a single value of lung centroid pressure is presumed as everyone’s standard. On the contrary, we considered that immersed respiratory compliance is disparate among a homogenous adult group (young, healthy, sporty). We wanted to substantiate this ample scattering for two reasons: (i) it may question the European standard used in designing dive-breathing devices; (ii) it may contribute to understand the diverse individual figures of immersed work of breathing. Resting spirometric measurements of lung volumes and the pressure–volume curve of the respiratory system were assessed for 18 subjects in two body positions (upright Up, and supine Sup). Measurements were taken in air (Air) and with subjects immersed up to the sternal notch (Imm). Compliance of the respiratory system (Crs) was calculated from pressure–volume curves for each condition. A median 60.45% reduction in Crs was recorded between Up-Air and Up-Imm (1.68 vs 0.66 L/kPa), with individual reductions ranging from 16.8 to 82.7%. We hypothesize that the previously disregarded scattering of immersion-reduced respiratory compliance might participate to substantial differences in immersed work of breathing.

Derivation of recruitment function from the pressure–volume curve in an acute lung injury model

2015 ◽  
Vol 205 ◽  
pp. 16-20 ◽  
Author(s):  
Yoshihiro Uzawa ◽  
Mikiya Otsuji ◽  
Koichi Nakazawa ◽  
Wei Fan ◽  
Yoshitsugu Yamada
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Volume Curve ◽  
Pressure Volume Curve ◽  
Injury Model ◽  
Lung Injury Model

Elastic constants of inflated lobes of dog lungs

1976 ◽  
Vol 40 (4) ◽  
pp. 508-513 ◽  
Author(s):  
S. J. Lai-Fook ◽  
T. A. Wilson ◽  
R. E. Hyatt ◽  
J. R. Rodarte
Keyword(s):  
Bulk Modulus ◽  
Young’S Modulus ◽  
Elastic Constants ◽  
Young's Modulus ◽  
Poisson Ratio ◽  
Inflation Pressure ◽  
Initial State ◽  
Volume Curve ◽  
Pressure Volume Curve ◽  
Indentation Tests

The elastic constants of dog lungs were determined at various degrees of inflation. In one set of experiments, the lobes were subjected to deformations that approximated the conditions of uniaxial loading. These data, together with the bulk modulus data obtained from the local slope of the pressure-volume curve, were used to determine the two elastic moduli that are needed to describe small nonuniform deformations about an initial state of uniform inflation. The bulk modulus was approximately 4 times the inflation pressure, and Young's modulus was approximately 1.5 times the inflation pressure. In a second set of experiments, lobes were subjected to indentation tests using cylindric punches 1–3 cm in diameter. The value for Young's modulus obtained from these data was slightly higher, approximately twice the inflation pressure. These experiments indicate that the lung is much more easily deformable in shear than in dilatation and that the Poisson ratio for the lung is high, approximately 0.43.

Lung volumes and alveolar expansion pattern in immature rabbits treated with serum-diluted surfactant

2004 ◽  
Vol 97 (4) ◽  
pp. 1408-1413 ◽  
Author(s):  
Yongmei Xu ◽  
Tsutomu Kobayashi ◽  
Xiaoguang Cui ◽  
Keisuke Ohta ◽  
Chiharu Kabata ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Distress Syndrome ◽  
Ringer Solution ◽  
Natural Surfactant ◽  
Volume Curve ◽  
Pressure Volume Curve ◽  
Expansion Pattern

In acute respiratory distress syndrome, mechanical ventilation often induces alveolar overdistension aggravating the primary insult. To examine the mechanism of overdistension, surfactant-deficient immature rabbits were anesthetized with pentobarbital sodium, and their lungs were treated with serum-diluted modified natural surfactant (porcine lung extract; 2 mg/ml, 10 ml/kg). By mechanical ventilation with a peak inspiration pressure of 22.5 cmH2O, the animals had a tidal volume of 14.7 ml/kg (mean), when 2.5 cmH2O positive end-expiratory pressure was added. This volume was similar to that in animals treated with nondiluted modified natural surfactant (24 mg/ml in Ringer solution, 10 ml/kg). However, the lungs fixed at 10 cmH2O on the deflation limbs of the pressure-volume curve had the largest alveolar/alveolar duct profiles (≥48,000 μm2), accounting for 38% of the terminal air spaces, and the smallest (<6,000 μm2), accounting for 31%. These values were higher than those in animals treated with nondiluted modified natural surfactant ( P < 0.05). We conclude that administration of serum-diluted surfactant to immature neonatal lungs leads to patchy overdistension of terminal air spaces, similar to the expansion pattern that may be seen after dilution of endogenous surfactant with proteinaceous edema fluid in acute respiratory distress syndrome.

Improved measurements of shear modulus and pleural membrane tension of the lung

1979 ◽  
Vol 47 (1) ◽  
pp. 175-181 ◽  
Author(s):  
M. A. Hajji ◽  
T. A. Wilson ◽  
S. J. Lai-Fook
Keyword(s):  
Shear Modulus ◽  
Transpulmonary Pressure ◽  
Elastic Half Space ◽  
Concentrated Force ◽  
Membrane Area ◽  
Volume Curve ◽  
Pressure Volume Curve ◽  
Pressure Independent ◽  
Work Done ◽  
The Continuum

The continuum solution for the deformation of an elastic half space covered by a membrane is used to interpret measurements of the indentation of lung lobes under a column of fluid. The shear modulus mu of the underlying parenchyma is found to be approximately 0.7 times transpulmonary pressure, independent of species size. The tension in the pleural membrane T increases rapidly with increasing membrane area. For dog lungs, the value of T is 10(3) to 10(4) dyn/cm. For the larger species tested, pigs and horses, T is larger. The continuum solution shows that a concentrated force applied to the pleural surface is distributed over a distance T/mu as it is transmitted across the pleural membrane. The membrane is important in determining the displacement produced by forces that act within a region that is small compared to this distance, approximately 2 cm for dog lungs. By comparing the tension-area curve of the pleural membrane with the pressure-volume curve of the lobe, it is found that the pleural membrane contributes about 20% of the work done by the lung during deflation.

Pressure-Volume Curve of the Remaining Lung after Lung Resection

1989 ◽  
Vol 21 (3-4) ◽  
pp. 168-174
Author(s):  
S. Hatakeyama ◽  
K. Harada ◽  
N. Saoyama ◽  
Y. Monden
Keyword(s):  
Lung Resection ◽  
Volume Curve ◽  
Pressure Volume Curve
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